Compressor And Turbocharger

ABSTRACT

A radial compressor with a compressor rotor having moving blades and a compressor housing receiving a diffuser. The diffuser ( 13 ) delimits at least in sections a flow passage leading away from the moving blades of the compressor rotor and exclusively has support blades.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The invention relates to a radial compressor and to a turbocharger. The invention present here relates to a radial compressor of a turbocharger and to a turbocharger having a radial compressor.

2. Description of the Related Art

Turbochargers comprise a compressor and a turbine. In the turbine of a turbocharger, a first medium is expanded, and energy extracted in the process is utilised in the compressor of the turbocharger to compress a second medium.

A radial compressor of a turbocharger comprises a compressor housing and a compressor rotor. The compressor rotor of the radial compressor is subjected to axial inflow and radial outflow, the compressor rotor carries moving blades. The compressor housing accommodates an insert piece and a diffuser. The insert piece at least in sections delimits a flow passage leading towards the moving blades of the compressor rotor and the diffuser delimits a flow passage of the radial compressor leading away from the moving blades of the compressor rotor.

From EP 1 340 920 B1 a radial compressor with a diffuser is known, wherein the diffuser of the radial compressor disclosed comprises diffuser guide blades. Such diffuser guide blades of a diffuser of a radial compressor substantially determine the flow passage leading away from the moving blades of the compressor rotor. Here, seen over the circumference of the diffuser, a relatively high number of diffuser guide blades is arranged, namely at least 16 diffuser guide blades, which accordingly extend with a small circumferential distance from one another and have a relatively large length between a leading edge and a trailing edge.

SUMMARY OF THE INVENTION

One aspect of the present invention is based on creating a new type of radial compressor and a turbocharger having such a radial compressor.

According to one aspect of the invention, the diffuser exclusively comprises support blades. The diffuser according to one aspect of the invention does not comprise any diffuser guide blades but merely support blades. In contrast with diffuser guide blades, the support blades do not substantially determine the flow passage leading away from the moving blades of the compressor rotor. The flow of the compressed medium is practically not influenced at all by the support blades. Such a diffuser makes it possible to combine the advantages of diffusers bladed with diffuser guide blades with the advantages of bladeless diffusers. In particular, the so-called characteristic diagram of the radial compressor is not restricted.

According to an advantageous further development, the diffuser comprises three to ten support blades distributed over its circumference, preferably between three to seven support blades. Such a low number of support blades is preferred to maintain the advantages of bladeless diffusers.

According to an advantageous further development, edges of the support blades located radially inside lie on a diameter d3, wherein the following applies to the diameter d3, on which the radially inner edges of the support blades lie: 1.2*d2≤d3≤1.35*d2. These details also served for maintaining the advantages of bladeless diffusers.

According to an advantageous further development, edges of the support blades located radially outside lie on a diameter. The following applies to a length L of the support blades defined by the distance between radially inner edges and radially outer edges: 0.1*d2≤L≤0.35*d2, wherein d2 is the outer diameter of the compressor rotor of the radial compressor. With such a length of the support blades, the advantages of bladeless diffusers can be maintained.

Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred further developments of the invention are obtained from the subclaims and the following description. Exemplary embodiments of the invention are explained in more detail by way of the drawing without being restricted to this.

There it shows:

FIG. 1 is an axial section through a detail of a radial compressor; and

FIG. 2 is a view of a diffuser of the radial compressor in viewing direction II of FIG. 1.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The invention relates a radial compressor and to a turbocharger with a radial compressor.

The person skilled in the art addressed here is familiar with the fundamental construction of a turbocharger. It is pointed out here that a turbocharger comprises a compressor and a turbine. In the turbine of the turbocharger, a first medium, in particular exhaust gas, is expanded and energy extracted in the process. The energy extracted in the turbine during the expansion of the first medium is utilised in the compressor of the turbocharger in order to compress a second medium, in particular charge air.

The invention present here relates to a turbocharger and to a radial compressor for a turbocharger, wherein a radial compressor is subjected to the inflow in the axial direction of medium to be compressed and outflow of the compressed medium in the radial direction.

The turbine of a turbocharger comprises a turbine rotor and a turbine housing. The compressor, namely the radial compressor 10, comprises a compressor housing 11 and a compressor rotor 14. Turbine rotor and compressor rotor 14 are coupled via a shaft which is mounted in a bearing housing 15. The bearing housing 15, on the one hand, is connected to the turbine housing of the turbine and, on the other hand, to the compressor housing 11 of the radial compressor 10.

FIG. 1, furthermore, shows an insert piece 12 and a diffuser 13. The insert piece 12 delimits a flow passage leading towards the moving blades of the compressor rotor 14 and the diffuser 13 delimits, at least in sections, in each case, a flow passage leading away from the moving blades of the compressor rotor 14.

The diffuser 13 of the radial compressor 10 according to one aspect of the invention does not have any diffuser guide blades that substantially define the flow conduct of the medium upstream of the compressor rotor 14, but merely support blades 16, which serves for simplified assembly and simplified installation of the diffuser 13 in the compressor housing 11.

Over the circumference of the diffuser 13, between three and ten support blades 16, preferably between three and seven support blades 16, particularly preferably between four and six support blades 16 are distributed. As is evident from FIG. 2, support blades 16 are distributed over the circumference of the diffuser 13 in the shown preferred exemplary embodiment.

Between the individual support blades 16, a relatively large distance is formed, in particular seen in the radial direction, there is no overlap between adjacent support blades 16. Accordingly, the support blades 16 practically do not at all influence a flow of the compressed medium downstream of the moving blades 14 of the compressor rotor 14. The distance between directly adjacent support blades 16 seen in the circumferential direction amounts to at least 10°, preferably at least 20°, particularly preferably at least 30°. In this angular range, none of the support blades 16 then extends seen in the radial direction and circumferential direction. Accordingly, the flow of the compressed medium can flow past in this angular range in an unobstructed and non-deflected manner.

Radially inner edges 17 of the support blades 16, which are also referred to as leading edges, lie on a circle or a circular contour with a diameter d3. The following applies to this diameter d3 on which the radially inner edges 17 of the support blades 16 lie: 1.2*d2≤d3≤1.35*d2, wherein d2 is the outer diameter of the compressor rotor 14 of the radial compressor.

In addition to the radially inner edges 17, the support blades 16 also comprise radially outer edges 18, which are also referred to as trailing edges. A distance between the radially inner edges 17 and the radially outer edges 18 defines a length L of the support blades 16. The following applies to the length L: 0.1*d2≤L≤0.03*d2, wherein d2 in turn is the outer diameter of the compressor rotor 14.

The radially outer edges 18 lie on a circular contour with a diameter d4. The following applies to this diameter d4, on which the radially outer edges 18 of the support blades 16 lie: 1.4*d2≤d4≤1.55*d2, wherein d2 in turn is the outer diameter of the compressor rotor 14 of the radial compressor 10.

Accordingly, a radial compressor 10 or a turbocharger with a radial compressor 10 is proposed with the invention present here, wherein the diffuser 13 of the radial compressor 10 comprises support blades 16, which have a relatively short length L and a relatively short radial extension, which is defined by the differential d4−d3, and which in addition, seen in the circumferential direction, are located a relatively large distance from one another. In this way, the advantages of bladeless diffusers can be maintained. The diffuser 13 can be simply mounted in the compressor housing 11.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto. 

What is claimed is:
 1. A radial compressor, comprising: a compressor rotor having moving blades; a diffuser that exclusively comprises a plurality of support blades and which delimits at least in sections a flow passage leading away from the moving blades of the compressor rotor; and a compressor housing configured to receive the diffuser, wherein the diffuser.
 2. The radial compressor according to claim 1, wherein the diffuser comprises three to ten support blades distributed over its circumference.
 3. The radial compressor according to claim 1, wherein the diffuser comprises three to seven support blades distributed over its circumference.
 4. The radial compressor according to claim 1, wherein radially inner edges of each of the plurality of support blades lie on a circular contour with a diameter d3.
 5. The radial compressor according to claim 4, wherein the diameter d3, on which the radially inner edges of each of the plurality of support blades lie satisfies: 1.2*d2≤d3≤1.35*d2, wherein: d2 is an outer diameter of a compressor rotor of the radial compressor.
 6. The radial compressor according to claims 1 to 5, wherein radially outer edges of each of the plurality of support blades lie on a circular contour with a diameter d4.
 7. The radial compressor according to claim 4, wherein the diameter, on which the radially outer edges of each of the plurality of support blades lie satisfies: 1.4*d2≤d4≤1.55*d2, wherein: d2 is an outer diameter of a compressor rotor of the radial compressor.
 8. The radial compressor according to claim 4, wherein a length L of each of the plurality of support blades defined by a distance between radially inner edges and radially outer edges satisfies the following: 0.1*d2≤L≤0.3*d2, wherein: d2 is an outer diameter of a compressor rotor of the radial compressor.
 9. A turbocharger, comprising: a turbine for expanding a first medium; and a radial compressor for compressing a second medium utilising energy extracted in the turbine during expansion of the first medium, comprising: a compressor rotor having moving blades; a diffuser that exclusively comprises a plurality of support blades and which delimits at least in sections a flow passage leading away from the moving blades of the compressor rotor; and a compressor housing configured to receive the diffuser, wherein the diffuser. 